Stacking stars with Hugin's help (show and tell)
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Monkey
Oct 26, 2013, 9:01:17 AM10/26/13
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Hi all,
Attached are a couple of images showing what I was able to do with Hugin's help.
single.jpg is a single 30-second fisheye exposure of the night sky, while stack.jpg is the averaged result of about 45 such images.
I converted the RAW camera files to TIFFs in Photoshop (which is quick and has good automated hot-pixel removal), then made a bitmap of points identifying about 30 of the brightest stars. I used parts of my own previously-written library to track these stars across the sequence of images, and then generated the control points to add to a .pto file of the images - rather than linking each image to every other, this only generated points from each image to image 0.
Hugin was able to optimise the images really well, then I wrote another piece of code to average the remapped TIFFs to a 32-bit .pfm, which was then opened in Photoshop and had the levels fiddled with until I got the result attached.
The attached are scaled down to 25%. The residual circular streaking you can see is down to regular noise in the camera's sensor, as I didn't use a dark frame. About midway between the bright star in the bottom half of the image and the glowing tree on the left, you might see what looks like a small diagonal streak - it's not a flare or meteor or anything like that, but five stars in Brocchi's Cluster which are surprisingly well-aligned.
In future I plan to automate a little more of this process - perhaps writing a simple GUI for directly opening RAW files and tracking stars to create a .pto file for Hugin to optimise, and then a stacker which can work on the original RAW data (which, with enough images, means you can do away with Bayer interpolation)
David
Attached are a couple of images showing what I was able to do with Hugin's help.
single.jpg is a single 30-second fisheye exposure of the night sky, while stack.jpg is the averaged result of about 45 such images.
I converted the RAW camera files to TIFFs in Photoshop (which is quick and has good automated hot-pixel removal), then made a bitmap of points identifying about 30 of the brightest stars. I used parts of my own previously-written library to track these stars across the sequence of images, and then generated the control points to add to a .pto file of the images - rather than linking each image to every other, this only generated points from each image to image 0.
Hugin was able to optimise the images really well, then I wrote another piece of code to average the remapped TIFFs to a 32-bit .pfm, which was then opened in Photoshop and had the levels fiddled with until I got the result attached.
The attached are scaled down to 25%. The residual circular streaking you can see is down to regular noise in the camera's sensor, as I didn't use a dark frame. About midway between the bright star in the bottom half of the image and the glowing tree on the left, you might see what looks like a small diagonal streak - it's not a flare or meteor or anything like that, but five stars in Brocchi's Cluster which are surprisingly well-aligned.
In future I plan to automate a little more of this process - perhaps writing a simple GUI for directly opening RAW files and tracking stars to create a .pto file for Hugin to optimise, and then a stacker which can work on the original RAW data (which, with enough images, means you can do away with Bayer interpolation)
David
David W. Jones
Oct 26, 2013, 9:55:34 PM10/26/13
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On 10/26/2013 03:01 AM, Monkey wrote:
> The attached are scaled down to 25%. The residual circular streaking you
> can see is down to regular noise in the camera's sensor, as I didn't use
> a dark frame.
Definitely do a dark frame. It will not only deal with regular noise, it
> The attached are scaled down to 25%. The residual circular streaking you
> can see is down to regular noise in the camera's sensor, as I didn't use
> a dark frame.
will also catch any hot pixels.
--
David W. Jones
gnome...@gmail.com
wandering the landscape of god
http://dancingtreefrog.com
David Haberthür
Oct 27, 2013, 7:09:29 AM10/27/13
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Ciao David.
Not to 'curb your enthusiasm' with developing something yourself to ge
the nice looking images: have you looked at http://starstax.net/ ?
Or do you not want to generate startrails, but generate high quality
images of a 'non-moving' sky with averaging multiple exposures?
David/Habi
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Not to 'curb your enthusiasm' with developing something yourself to ge
the nice looking images: have you looked at http://starstax.net/ ?
Or do you not want to generate startrails, but generate high quality
images of a 'non-moving' sky with averaging multiple exposures?
David/Habi
> A list of frequently asked questions is available at:
> http://wiki.panotools.org/Hugin_FAQ
> ---
> You received this message because you are subscribed to the Google Groups
> "hugin and other free panoramic software" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to hugin-ptx+...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/hugin-ptx/5e7beab5-a9a7-4d89-9ea6-0230d6ebbea2%40googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
Monkey
Oct 28, 2013, 9:08:29 AM10/28/13
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Nope, I wanted to remap the images so as not to generate star trails. There is software around that does this, but I've never found one I'm completely happy with - either they only support simple remapping (sometimes only translation, sometimes also rotation but that isn't always enough), or the interface is bizarre, or they just plain crash.
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